Are There Unusually Effective Occupational Safety and Health Inspectors and Inspection Practices?

by Amelia Haviland, Regan Main, Wayne B. Gray, Jing Xia, John Mendeloff

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This study examines the role of inspector “style” in influencing the effectiveness of inspections in reducing injury rates. It addresses four main research questions: 1) How much do inspectors vary in the way that they carry out inspections in terms of practices that might have an impact on inspection effectiveness? 2) How much of the variation in inspection outcomes (change in injury rates) can be explained by which inspector carried out the inspection? 3) How much of the variation in inspection outcomes can be explained by which Cal-OSHA district the inspector was associated with? 4) Are certain inspection practices associated with better inspection outcomes? The data used to help answer these questions are inspections by the California OSHA program from 2002 to 2007 with a subset linked to injury reports from the Workers’ Compensation Information System and employment data from the Employment Development Department.The short answers to the questions are as follows: 1) The amount of variation among inspectors in their practices appears to be quite large. 2) About 3% of the variation in inspection outcomes (change in injury rates) can be explained by the identity of the inspector. More inspectors have unusually good or poor outcomes than would have occurred due to chance. 3) Although 1 or 2 districts appeared to have smaller reductions in injuries than the others, the statistical significance of the differences was marginal. 4) We were not able to identify inspection practices that were associated with better inspection outcomes. However, we did find that more experienced inspectors had better outcomes.

Table of Contents

  • Section One


  • Section Two

    Data Sources and Methods

  • Section Three


  • Section Four

    Conclusions and Implications

  • Appendix A

    Construction of the Data Sets

  • Appendix B

    Variation in Inspection Practices, Inspector Level, by Inspection Type

  • Appendix C

    Variation in Inspection Practices, District Level, by Inspection Type

  • Appendix D

    Modifications to the WCIS and ODI Data

  • Appendix E

    Model Results for Table 5

This working paper was prepared by the RAND Center for Health and Safety in the Workplace for the California Commission on Health and Safety and Workers' Compensation.

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